What will happen in the power-sharing talks?

The South African president, Thabo Mbeki, will mediate the signing of a memorandum of understanding between the ruling Zanu-PF and the two factions of the opposition Movement for Democratic Change (MDC) to outline a framework for a formal agreement to try to resolve Zimbabwe's political and economic crisis. Robert Mugabe and Morgan Tsvangirai will both attend the signing in Harare.

What is Tsvangirai likely to agree to?

Tsvangirai has previously refused to sign even a framework deal unless government militias stop their violence. One of his key demands has been that the mediation process expands beyond Mbeki, whom he has accused of favouring Mugabe.

Last week it was announced a group of senior diplomats, including representatives from the UN, the African Union and the South African Development Community, would assist Mbeki in the negotiations, widening the mediation process.

The MDC says it is open to a government of national healing - but only one with moderate ruling party members, not Mugabe.

What will Mugabe do next?

At the time of the election, Mugabe said he would enter talks with the opposition after the vote, suggesting he would try to form the kind of "government of national unity" proposed by the African Union by co-opting some members of the MDC.

But Tsvangirai has dismissed this idea. It would also be dangerous because of the possibility of reprisals against those who refused to take part, and against Zimbabweans who did not vote.

Zanu-PF has said it is open to power-sharing but only if Mugabe heads any unity government.

What happened in the presidential run-off?

Tsvangirai was Mugabe's main opponent but withdrew before the polls, saying he could not ask people to endanger their lives by voting for him.

Nonetheless, the electoral commission ruled that Tsvangirai had pulled out too late to cancel the election and it went ahead. In the end, Mugabe won more than 85% of the vote but the MDC said most people stayed away from voting. There have been at least nine murders since the run-off last month.

Was it possible to vote MDC?

People could have voted for Tsvangirai, whose name remained on the ballot despite his withdrawal. But few would have taken the risk. Before evidence of election rigging was revealed in a Guardian film, there had been numerous reports of opposition activists being assaulted and killed by ruling party militants. Tsvangirai said the structure of the MDC itself was being targeted.

In the run-up to the election, the party was prevented from holding rallies. Tsvangirai was detained twice and the party's secretary general, Tendai Biti, was arrested and charged with treason.

Who monitored the election?

A regional group, the Southern African Development Community, sent more than 200 observers. Zimbabwean pro-democracy groups tried to field observers, although they met repeated bureaucratic obstacles. The observers could not move freely, particularly in the areas that had witnessed the worst pre-election violence.

What was the view of the international community?

International opinion hardened against Mugabe. The EU backed Tsvangirai's position on a national unity government and said it believed that if there were to be one, Tsvangirai should lead it to reflect "the will of the Zimbabwean people". Gordon Brown said the UN should send an envoy to Zimbabwe to begin discussions on a transition agreement, and the US drafted a UN security council resolution for further sanctions against Zimbabwe.

Are there divisions within Zanu-PF?

Zanu-PF is deeply divided over the course Mugabe is taking. One of the vice-presidents, Joice Mujuru, and her husband, Solomon, are thought to lead a dissenting faction in the party's politburo. Another is led by a former finance minister, Simba Makoni, who stood against Mugabe in the first round of the presidential elections. But since Zanu-PF's loss of its majority in the house of assembly elections in March, the politburo has ceded power to a narrower group of hardliners and generals in joint operations command, led by Mugabe's lieutenant, Emmerson Mnangagwa.

What has been the impact of this on the economy?

Zimbabwe's economic collapse under Mugabe's rule has flooded neighbouring countries with millions of refugees and saddled the once-prosperous country with crippling food and fuel shortages.

On July 21, the central bank in Zimbabwe issued a new 100 billion dollar note in an attempt to keep up with shortages of cash and the world's worst inflation running at 2.2m per cent.